Combined fuse clip and switch blade mounting assembly



g- 25, 1970 J. J. RUSENKO Q 3,525,838

COMBINED FUSE CLIP AND SWITCH BLADE MOUNTING ASSEMBLY Filed Dec. 16, 1968 United States Patent 3,525,838 COMBINED FUSE CLIP AND SWITCH BLADE MOUNTING ASSEMBLY James J. Rusenko, Milwaukee, Wis., assiguor to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Filed Dec. 16, 1968, Ser. No. 784,061 Int. Cl.'H01h 1/42 US. Cl. 200-166 5 Claims ABSTRACT OF THE DISCLOSURE A knife switch blade is pivotally mounted between a first electrically conductive member and the vertical leg of an L-shaped bracket by a headed fastener. A spring washer is disposed about the fastener on the outer side of the bracket to bias the members into good electrically conductive engagement. The horizontal leg of the bracket and a similar leg of a fuse clip are secured to the switch base in stacked relation, the fuse clip further having an upwardly extending leg formed to engage the end of a fuse and bias it against the electrically conductive member.

BACKGROUND OF THE INVENTION This invention relates to mounting assemblies for providing the combined support for a fuse and pivotal knife blade in a fusible safety switch or the like.

Prior art fusible safety switch designs commonly provided separate and distinct mountings for the knife blade and the fuse, each member being mounted upon a common electrically conductive connecting plate to electrically join the fuse to the switch blade. Present design specifications of fusible safety switches call for reductions in overall switch size, parts and materials in an effort to meet the consumer demands and still combat the rising costs of material and assembly. A new mounting assembly for the fuse and knife blade is provided herein which occupies less area upon the switch base and affords a substantial cost reduction over the prior art designs. In the new design the fuse clip and blade mount are combined into a single unit in which one member is common to both the clip and blade mount. By so doing, the number of electrically conductive joints has been reduced to enhance the current carrying function of the assembly, and the use of copper in the assembly is restricted to only the member common to both functions.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a combined fuse clip and knife blade mounting assembly which is compact in size and comprises a relatively few separate parts to reduce assembly time and cost therefor.

It is a further object of this invention to provide a combined fuse clip and knife blade mounting assembly in which the use of a more costly, good electrical conducting material is reduced to a single member which is common to both functions of the assembly.

These and other objects and advantages of the invention will become more readily apparent in the following specification and claims when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a portion of a switch base 3,525,838 Patented Aug". 25, 1970 DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1 of the drawings there is shown a fragmentary portion of an insulating mounting base 2 of a fusible safety switch or the like. One knife switch is assembled to this portion of the base 2 and comprises the combined fuse clip and blade mounting assembly 4 of this invention, a pivotable knife blade 6 and a stationary contact clip assembly 8. In safety switches one or more such knife switches are employed, each being mounted upon the base 2 in side-by-side alinement. While not specifically shown in the drawings, the blades 6 of the respective switches are commonly provided with upwardly extending hooks or the like to connect each blade to a common actuating bail of the switch operating mechanism to effect simultaneous pivotal movement of the blades between their respective open and closed positions.

With reference particularly to the cross-sectional view of the mounting assembly in FIG. 3, an L-shaped bracket 10, preferably formed of steel, is secured to the base 2 by a screw 12 which extends through a clearance opening in the base 2 and takes into a threaded opening formed in the horizontal leg of bracket 10. A rectangular plate 14, formed of a good electrically conducting material such as copper, is positioned to rest upon the horizontal leg of bracket 10 and extend vertically therefrom parallel to the vertical leg thereof. Plate 14 and the vertical leg of bracket 10 are provided with alined openings for receiving a screw 16 therethrough, as is the right-hand end of knife blade 6 which is disposed between the plate 14 and bracket 10. The opening in plate 14 is countersunk to permit the head of screw 16 to be flush with the outer surface thereon when screw 16 is secured in place. The outer end of screw 16 protrudes beyond the bracket 10 and receives a spring washer 18 and nut 20 thereon. The latter is tightened upon the washer 18 to draw the plate 14 and knife blade 6 against the inner face of the vertical leg of bracket 10, thereby providing a good electrical connection between the members while affording knife blade 6 pivotal movement about the screw 16. The engagement of the lower edge of the plate 14 with the upper surface of the horizontal bracket leg rigidly positions the plate against rotational movement with the knife blade 6 without necessitating additional securing means.

A fuse clip member 22, formed of spring steel or the like, has a horizontal leg which is rigidly trapped between the base 2 and the horizontal leg of bracket 10, there being a clearance hole provided in the leg of spring clip 22 for screw 12. Spring clip 22 further has an upwardly extending leg which is suitably offset inwardly toward the plate 14 and formed to engage the surface of plate 14 in its normal position. The extreme outer end of the upwardly extending leg of spring clip 22 is flared outwardly away from plate 14 to facilitate the insertion of the blade terminal 24 of a fuse 26 between the plate 14 and fuse clip 22. The end of screw 12 limits the depth to which the fuse blade 24 may be inserted within the assembly. The deflection of spring clip 22 by the insertion of fuse blade 24 causes the spring clip to exert a strong bias on the entire hinge joint and fuse clip assembly, thereby urging the fuse blade 24 toward good electrical engagement with the fiat face of copper plate 14. The spring force applied by the leg of spring clip 22 eliminates the use of a second spring washer required to meet certain commercial standards and thereby further reduces the number of parts of the assembly.

In the foregoing assembly, the fuse 26 is electrically connected to the knife blade 6 through two electrical joints, namely that between the fuse blade 24 and copper plate 14 and the joint between the latter and the knife blade 6. Since no other member of the mounting assembly 4 carries the electrical current, it is only necessary that plate 14 be made of copper or other good electrically conducting material to reduce the cost of the assembly.

A modified mounting assembly 28 for lower ampere rated switches is shown in FIG. 4. The fuses for lower rated devices have cylindrical terminal ends as opposed to the blade type and therefore require a somewhat different configuration of the spring clip. Also, the amount of copper or other suitable material may be reduced in the lower rated devices.

The assembly 28 comprises an L-shaped steel bracket 30 and a generally U-shaped spring clip 32. A knife blade 34 of the switch is disposed between the vertical leg of bracket 30 and the right-hand leg of spring clip 32. A rivet 36 passes through alined clearance openings in the members 30, 32 and 34 and has a spring washer 38 disposed over its outer end to engage the outer face of the vertical leg of bracket 30. The outer end of rivet 36 is turned over to secure the members together under the compressive force of spring washer 38 to provide a good electrically conductive joint while permitting pivotal movement of the blade 34.

The mounting assembly 28 is secured to the insulating switch base by a screw 40 which extends upwardly through clearance holes in the base and horizontal leg of bracket 30 to take into a threaded opening in the spring clip 32. The left-hand leg of spring clip 32 has an arcuate configuration which conforms to the cylindrical terminal end of a fuse 42 to firmly hold the fuse in place. The spring clip 32 biases the fuse 42 toward good electrical engagement with the right-hand leg thereof.

Thus the mounting assembly 28 also has two electrically conductive joints, one being from fuse 42 to the right-hand leg of spring clip 32 and the other from the latter leg to the knife blade 34. In this version the entire spring clip 32 is made of a good electrically conducting material since the reduction in material thickness thereof permitted in the lower rated devices offsets the cost thereof to allow this assembly to comprise one less piece. However, it should be noted that the spring clip could be made of spring steel or the like and the right-hand leg of spring clip 32 could be replaced by a copper or the like plate such as in the assembly 4 if the cost of producing the entire spring clip 32 of such material becomes prohibitive.

What is claimed is:

1. A combined fuse clip and knife blade mounting assembly for a fusible safety switch or the like comprising, in combination;

a rigid bracket member having a horizontal and a vertical leg;

a resilient fuse clip member formed of spring material and having a horizontal leg and at least one substantially vertical leg;

means securing the horizontal legs of said bracket member and said fuse clip member together and to an insulating switch base in stacked relationship;

means formed of good electrically conducting material disposed in parallel, spaced apart relationship to said vertical leg of said bracket member;

a knife blade pivotally mounted between said means and said vertical leg of said bracket member by headed fastener means extending therethrough;

a spring washer disposed between one end of said headed fastener and one side of said vertical leg of said bracket member to bias said means and said knife blade into good face-to-face electrical engagement with each other; and

wherein said substantially vertical leg of said fuse clip member cooperates with said means to provide a fuse retaining pocket therebetween, said vertical leg of said fuse clip member being formed and to retain and bias a fuse against said means in good electrical engagement therewith.

2. The combination according to claim 1 wherein said means formed of good electrically conducting material comprises a plate member having at least one fiat edge which rests upon the upper surface of the horizontal leg of said bracket member to prevent rotational movement of said plate upon movement of said knife blade.

3. The combination according to claim 1 wherein said means formed of good electrically conducting material comprises a second vertical leg on said fuse clip member.

4. The combination according to claim 1 wherein said means securing the horizontal legs of said bracket member and said fuse clip member together and to an insulating switch base in stacked relationship comprises a screw member extending through alined openings in said base and said horizontal leg of said fuse clip member to take into an alined threaded opening in said horizontal leg of said bracket member, and wherein the end of the threaded shank portion of said screw projects beyond said horizontal leg of said bracket member to serve as a stop for limiting the depth to which said fuse may be inserted within said pocket.

5. A combined fuse clip and knife blade mounting as sembly for a fusible safety switch or the like comprising, in combination;

an insulating switch base;

a bracket member and a spring clip member each having horizontal leg portions secured upon the surface of said insulating base in stacked relationship by a threaded fastener which passes through clearance openings in said base and one of said leg portions to take into a corresponding threaded opening in the other leg portion;

a vertically extending leg portion on said bracket;

a hole in said vertically extending leg portion;

a knife blade positioned adjacent one surface of said vertically extending leg portion;

a hole in said knife blade alined with said hole in said vertically extending leg;

a plate member formed of good electrically conductive material disposed in parallel, spaced apart relationship to said vertically extending leg and in faceto-face engagement with an opposite surface of said knife blade, said plate member having a flat edge in abutting engagement with the upper surface of said horizontal leg portion of said bracket;

a hole in said plate member alined with said hole in said vertically extending leg of said bracket;

headed fastener means disposed through said alined openings in said plate member, said knife blade and said vertically extending leg to secure said members together and permit pivotal movement of said knife blade about said fastener means;

a spring washer disposed about said fastener means at one end thereof to bias said members together and into good electrically conducting engagement; and

an upwardly extending leg portion on said spring clip member, said last mentioned leg portion being olf- 5 set toward said plate member to cooperate therewith to provide a fuse retaining pocket therepetween, said leg portion biasing a fuse inserted within said pocket into good electrically conductive engagement with said plate member.

References Cited UNITED STATES PATENTS 2,458,511 1/ 1949 Harlow 331-9 6 2,487,545 11/1949 Harlow 200162 3,265,830 8/ 1966 Kobryner. 3,287,553 11/1966 Rys n 200-162 5 HERMAN 0. JONES, Primary Examiner US. 01. X.R. 

